U.S. patent number 10,428,161 [Application Number 15/760,703] was granted by the patent office on 2019-10-01 for method for producing modified solution-polymerized diene rubber to be blended with silica, and rubber composition containing same.
This patent grant is currently assigned to ERIC Inc.. The grantee listed for this patent is ETIC Inc.. Invention is credited to Iwakazu Hattori, Hisao Ono.
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United States Patent |
10,428,161 |
Hattori , et al. |
October 1, 2019 |
**Please see images for:
( Certificate of Correction ) ** |
Method for producing modified solution-polymerized diene rubber to
be blended with silica, and rubber composition containing same
Abstract
Studies have been made for the purpose of achieving both the
improvement in the storage stability of a solution-polymerized
diene rubber that is modified with an alkoxysilane compound and the
improvement in the physical properties of the diene rubber when
blended with silica. Thus, a production method whereby it becomes
possible to produce a modified solution-polymerized diene rubber
having good storage stability and high reactivity with silica is
developed, by introducing several tens percent of a three blanched
or four blanched component that has been coupled with a tin
compound into a modified solution-polymerized diene rubber, then
coagulating the resultant alkoxysilane modified diene rubber with
steam and then drying the coagulated product. In addition, the
physical properties of the rubber are further improved successfully
by introducing a highly reactive structure to a polymerization
initiation terminal of the rubber in the polymerization of the
rubber using an alkyl lithium as a polymerization initiator.
Inventors: |
Hattori; Iwakazu (Tokyo,
JP), Ono; Hisao (Tokyo, JP) |
Applicant: |
Name |
City |
State |
Country |
Type |
ETIC Inc. |
Tokyo |
N/A |
JP |
|
|
Assignee: |
ERIC Inc. (Tokyo,
JP)
|
Family
ID: |
58288471 |
Appl.
No.: |
15/760,703 |
Filed: |
September 18, 2015 |
PCT
Filed: |
September 18, 2015 |
PCT No.: |
PCT/JP2015/076805 |
371(c)(1),(2),(4) Date: |
March 16, 2018 |
PCT
Pub. No.: |
WO2017/046963 |
PCT
Pub. Date: |
March 23, 2017 |
Prior Publication Data
|
|
|
|
Document
Identifier |
Publication Date |
|
US 20180273650 A1 |
Sep 27, 2018 |
|
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
C08K
3/04 (20130101); C08K 3/36 (20130101); C08F
8/12 (20130101); C08L 15/00 (20130101); C08C
19/25 (20130101); C08F 8/42 (20130101); C08F
236/10 (20130101); C08C 2/06 (20130101); C08K
3/04 (20130101); C08L 15/00 (20130101); C08K
3/36 (20130101); C08L 15/00 (20130101) |
Current International
Class: |
C08F
8/42 (20060101); C08L 15/00 (20060101); C08K
3/04 (20060101); C08F 8/12 (20060101); C08C
2/06 (20060101); C08C 19/25 (20060101); C08K
3/36 (20060101); C08F 236/10 (20060101) |
Field of
Search: |
;524/572 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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1980575 |
|
Oct 2008 |
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EP |
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2130841 |
|
Dec 2009 |
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EP |
|
59-038209 |
|
Mar 1984 |
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JP |
|
62-227908 |
|
Oct 1987 |
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JP |
|
63-168402 |
|
Jul 1988 |
|
JP |
|
63-175001 |
|
Jul 1988 |
|
JP |
|
01-284503 |
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Nov 1989 |
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JP |
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2000-281835 |
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Oct 2000 |
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JP |
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2003-246817 |
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Sep 2003 |
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JP |
|
2004-018795 |
|
Jan 2004 |
|
JP |
|
2004018795 |
|
Jan 2004 |
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JP |
|
2004-331940 |
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Nov 2004 |
|
JP |
|
2006-257260 |
|
Sep 2006 |
|
JP |
|
2009-287018 |
|
Dec 2009 |
|
JP |
|
2013-053293 |
|
Mar 2013 |
|
JP |
|
2451693 |
|
May 2012 |
|
RU |
|
2484104 |
|
Jun 2013 |
|
RU |
|
WO 2008/029814 |
|
Mar 2008 |
|
WO |
|
Other References
PCT/JP2015/076805, Oct. 20, 2015, International Search Report and
Written Opinion. cited by applicant.
|
Primary Examiner: Egwim; Kelechi C
Attorney, Agent or Firm: Wolf, Greenfield & Sacks,
P.C.
Claims
The invention claimed is:
1. A method for producing a modified solution polymerized diene
rubber, comprising: i) initiating polymerization of a conjugated
diene compound and an aromatic vinyl compound in a hydrocarbon by
an organolithium compound or in the co-presence of a secondary
amine compound; ii) after completion of the polymerization, adding
a tin compound of formula (1) to treat the diene rubber so that the
content of three or more branched component is 5 to 30%; iii)
adding the silane compound of formula (2), whereby the content of
two-branched component of the diene rubber is less than 30%; and
iv) steam coagulating and drying the obtained polymer composition,
so that the content of two or more branched component increases by
10 to 50% with respect to the state before steam coagulation, and
wherein the modified solution polymerized diene rubber is thermally
stabilized to the extent that the Mooney viscosity (a) of the
rubber measured after said coagulation and drying, varies by not
more than 10 from the Mooney viscosity (b) of the rubber measured
when it is further heat-treated for 20 minutes with a subsequent
130.degree. C. roll mill, [Formula 1]
(R.sup.1).sub.n--Sn--(X).sub.4-n Formula (1) wherein R.sup.1 is an
alkyl group, an allyl group or aromatic group, wherein a carbon
number of R.sup.1 is 1 to 12 carbon atoms, X is a halogen compound
of iodine, bromine or chlorine, n is an integer of 0 or 1, [Formula
2] (R.sup.2O).sub.n--Si--(R.sup.3).sub.4-m Formula (2) wherein
R.sup.2 is an alkyl group, an allyl group or an aromatic group,
wherein a carbon number of R.sup.2 is 1 to 12, or an alkyl group,
an aromatic group or an allyl group containing a nitrogen atom in
these functional groups, R.sup.3 is a an alkyl group, an allyl
group or aromatic group, wherein a carbon number of R.sup.3 is
1-12, or an alkyl group, an aromatic group or allyl group,
containing an oxygen atom and/or a nitrogen atom in these
functional groups, m is an integer of 2 to 4.
2. The method for producing a modified solution polymerized diene
rubber according to claim 1, wherein polymerization is initiated in
the presence of an organolithium compound and a secondary amine
compound.
3. The method for producing a modified solution polymerized diene
rubber according to claim 1, wherein, after preliminarily
polymerizing isoprene with an organolithium compound, another
conjugated diene compound and an aromatic vinyl compound are
polymerized.
4. The method for producing a modified solution polymerization
diene rubber according to claim 1, wherein another conjugated diene
compound and the aromatic vinyl compound are polymerized after
preliminary polymerization in the presence of an organolithium
compound, a secondary amine compound, and isoprene.
5. The method for producing a modified solution polymerized diene
rubber according to claim 1, wherein steam coagulation and drying
in the step iv) is performed in such a way that the content of two
or more branched component increases by 20 to 40% with respect to
the state before the steam coagulation and drying.
6. The method for producing the modified solution polymerization
diene rubber according to claim 1, wherein, after preliminarily
polymerizing isoprene of not more than 10% by weight of the total
monomers with an organolithium compound, another conjugated diene
compound and the aromatic vinyl compound are polymerized.
7. The method for producing the modified solution polymerized diene
rubber according to claim 1, wherein after step iii) and before
step iv), addition of the metal halide compound of formula (3) in
an amount satisfying the condition of formula (4) is done, and then
the steam coagulation and drying of step iv) is performed, [Formula
3] (R.sup.4).sub.p-M-(X).sub.4-p Formula (3) wherein, M is a tin
atom or a silicon atom, R.sup.4 is an alkyl group or aromatic
group, wherein a carbon number of R.sup.4 is 1 to 12, or an allyl
group or a carboxy group, X is a halogen compound of iodine,
bromine or chlorine, p is an integer of 0 or 1, [Formula 4]
L-(4-n)A.ltoreq.(4-p)B.ltoreq.2L Formula (4) wherein, L is the
amount of moles of the organolithium compound added at the starting
of the polymerization, A is the amount of moles of the added tin
compound of formula (1), B is the added halogenated metal compound
of formula (3), and n and p are integers shown in formulae (1) and
(3), respectively.
8. A rubber composition prepared by the method according to claim
1, comprising silica of at least 20-150 phr for 100 phr of the
total rubber component, wherein said 100 phr of the total rubber
component contains at least 20 phr of the modified solution
polymerized diene rubber.
9. A rubber composition prepared by the method according to claim
1, comprising silica of at least 20-150 phr and carbon black of
5-30 phr for 100 phr of an entire rubber component, wherein said
100 phr of the total rubber component contains at least 20 phr of
the modified solution polymerized diene rubber according to claim
1.
Description
RELATED APPLICATION
This application is a national stage filing under 35 U.S.C. 371 of
International Patent Application Serial No. PCT/JP2015/076805,
filed Sep. 18, 2015, entitled "METHOD FOR PRODUCING MODIFIED
SOLUTION POLYMERIZED DIENE RUBBER TO BE BLENDED WITH SILICA, AND
RUBBER COMPOSITION CONTAINING THE SAME." The contents of this
application is incorporated herein by reference in its
entirety.
TECHNICAL FIELD
The present invention relates to silica-loaded for terminal
modified solution polymerized diene production process and a rubber
composition of the rubber having physical properties such as
excellent resilience and storage stability. The terminal modified
solution polymerized diene rubber obtained by the production
method, the higher the strength and rebound resilience, when used
in a rubber tire, it is optimal for automotive tire having a good
fuel efficiency.
BACKGROUND ART
Silica-containing rubber compositions are effective for making fuel
efficiency tires. To improve tan .delta. of a rebound resilience
test or a viscoelastic test, which is a laboratory indicator of
fuel efficiency, alkoxysilane modified solution polymerization
diene rubber with silica compound is effective. However, Si--OR
groups contained in the modified solution polymerization diene
rubber is hydrolyzed with moisture in the air, and further causes
condensation reaction, and therefore problematic in that molecular
weight increases during storage and the silica reactivity, which is
indispensable for improving physical properties, decreases.
On the other hand, to improve the rebound resilience and the like,
it is necessary to introduce a reactive functional group reacting
with silicas such as alkoxysilyl group, to the molecule of the
rubber at its one end. It has been considered that fuel efficiency
is improved when another one end that is starting end was also
modified, that is, both terminal-modified diene rubber is bonded to
silica, the movement is suppressed by the bondings. However, in
fact, it has also been found that when highly reactive functional
group such as an alkoxysilyl group was introduced to the both ends,
agglomerated silica cannot be efficiently dispersed by
kneading.
Therefore, functional groups at one terminal that does not include
an alkoxysilyl group is regarded as advantageous because silicas'
interaction with the rubber is relatively low in kneading, and
structures crosslinking with silica or other molecular structure
easily during vulcanization reaction are believed to be
advantageous, but there remains still many challenges in
preparations of silica-containing modified solution polymerization
diene rubber stable in industrial production and with good
quality.
As shown in Patent Documents 1 and 2, the inventors disclosed for
the first time the production method of solution polymerization
diene rubber having an alkoxysilyl group by reacting, after
polymerization of styrene and butadiene with alkyl lithium as a
polymerization initiator, alkoxysilane compounds having large
steric hindrance and hardly hydrolyzed, and started industrial
production. However, it was found later that the alkoxysilane
compound being lacking polar group containing N atom or the like,
and modified diene rubber of this compound is somewhat low
reactivity with silica.
Patent Document 3 discloses a production of modified SBR by
reacting an amino alkoxysilane compound after polymerizing styrene
and butadiene, alkyllithium as a polymerization initiator, and
evaluation results of only carbon black compound.
Patent Document 4 discloses silica compound SBR of good storage
stability, produced after the polymerization of styrene and
butadiene, with alkyllithium as a polymerization initiator, by
reacting in a specific proportion of amino alkoxysilane compounds
similar to those in Patent Document 3.
Patent Document 5 discloses a synthesis of a coupling SBR by adding
tin tetrachloride, after the polymerization of styrene and
butadiene with lithium morpholide as a polymerization initiator,
and results of evaluation of the physical properties of the product
but of only the carbon black compounded ones.
Patent Document 6 discloses a production method of polymers,
wherein the polymers are produced by reacting the amino alkoxy
silane compound after a block copolymerization of styrene and
butadiene, with an alkyl lithium or the like including an amino
group but not added to the silica as a polymerization initiator,
and further butadiene part is hydrogenated.
Patent Document 7 and Patent Document 8 disclose results of
evaluation of properties of a polymer as silica formulation reacted
by amino alkoxysilane compound after the polymerization of styrene
and butadiene, the amino alkyl lithium being added and reacted with
small amount of monomer and then used as initiator. However, the
polymerization initiator has a special structure, and therefore it
is difficult in industrial production to synthesize and to
manufacture stably.
Patent Document 9 discloses a SBR carbon black formulation which
was coupled with the halogenated tin compound after the
polymerization of styrene and butadiene with alkyl lithium as a
polymerization initiator, and prior to the reaction by the amino
alkoxysilane compound, wherein the amount of said halogenated tin
compound is half of the equivalent amount of the used alkyl
lithium.
However, in recent years the demand for improvement of low fuel
consumption of cars has become more and more stronger from the
viewpoints of prevention of global warming and energy issues, and
the like. Although silica compound tires are improved in fuel
economy compared to the carbon black compound tires, suitable
alkoxysilane-modified solution polymerization diene rubber
composition containing silica has a problem that a Mooney viscosity
(MV) is changed during storage, and the improvement request of
further low fuel consumption has become stronger. Patent Document
1: JPH06-51746(B1) Patent Document 2: JPH07-68307(B1) Patent
Document 3: JPH06-53768(B1) Patent Document 4: JP2013053293(A)
Patent Document 5: JPS59-38209(A) Patent Document 6: JP 3988495(B2)
Patent Document 7: JP 4289111(B2) Patent Document 8: JP4655706(B2)
Patent Document 9: JP 2625876(B2)
DISCLOSURE OF THE INVENTION
Problems to be Solved by the Invention
In such circumstances, an object of the present invention is to
provide terminal modified solution diene rubber and a rubber
composition thereof, wherein the rubber has a superior rebound
resilience and the like, good steam desolvation, excellent storage
stability of and excellent workability at the time of blending.
The Means to Solve the Problem
The present inventors have developed, by a result of intensive
studies on manufacturing method of conjugated diene rubber having
high rebound resilience and superior in storage stability, a
manufacturing method of modified solution polymerization diene
rubber, and completed the present invention. In the method, at
first, a small amount of fast vulcanization rate monomer is
polymerized in the presence of an organic lithium compound and
secondary amine compound, followed by polymerization of other
conjugated diene compound and an aromatic vinyl compound in a
hydrocarbon. After the completion of the polymerization, a specific
silane compound and a specific tin compound are added successively
and specific coupling efficiency were controlled into certain
ratio. Then, halogenated metal compounds are added under more
specific conditions in the absence of an active diene rubber,
followed by increasing of the coupling efficiency by steam
coagulation. Resulted modified solution polymerization diene rubber
was stable in productivity and storage stability was also good.
[1] A method for producing a modified solution polymerized diene
rubber, comprising:
i) initiating polymerization of a conjugated diene compound and an
aromatic vinyl compound in a hydrocarbon by an organolithium
compound or in the co-presence of a secondary amine compound;
ii) after completion of the polymerization, adding a tin compound
of formula (1) to treat the diene rubber so that the content of
three or more branched component is 5 to 30%;
iii) adding the silane compound of formula (2), whereby the content
of two-branched component of the diene rubber is less than 30%;
and
iv) steam coagulating and drying the obtained polymer composition,
so that the content of two or more branched component increases by
10 to 50% with respect to the state before steam coagulation, and
wherein the modified solution polymerized diene rubber is thermally
stabilized to the extent that the Mooney viscosity (a) of the
rubber measured after said coagulation and drying, varies by not
more than 10 from the Mooney viscosity (b) of the rubber measured
when it is further heat-treated for 20 minutes with a subsequent
130.degree. C. roll mill. [Formula 1]
(R.sup.1).sub.n--Sn--(X).sub.4-n Formula (1) wherein R.sup.1 is an
alkyl group, an allyl group or aromatic group, wherein a carbon
number of R.sup.1 is 1 to 12 carbon atoms, X is a halogen compound
of iodine, bromine or chlorine, n is an integer of 0 or 1, [Formula
2] (R.sup.2O).sub.n--Si--(R.sup.3).sub.4-m Formula (2) wherein
R.sup.2 is an alkyl group, an allyl group or an aromatic group,
wherein a carbon number of R.sup.2 is 1 to 12, or an alkyl group,
an aromatic group or an allyl group containing a nitrogen atom in
these functional groups, R.sup.3 is a an alkyl group, an allyl
group or aromatic group, wherein a carbon number of R.sup.3 is
1-12, or an alkyl group, an aromatic group or allyl group,
containing an oxygen atom and/or a nitrogen atom in these
functional groups, m is an integer of 2 to 4. [2] The method for
producing a modified solution polymerized diene rubber according to
the above mentioned [1], wherein polymerization is initiated in the
presence of an organolithium compound and a secondary amine
compound. [3] The method for producing a modified solution
polymerized diene rubber according to the above mentioned [1] or
[2], wherein, after preliminarily polymerizing isoprene with an
organolithium compound, another conjugated diene compound and an
aromatic vinyl compound are polymerized. [4] The method for
producing a modified solution polymerization diene rubber according
to any one of the above mentioned [1] to [3], wherein another
conjugated diene compound and the aromatic vinyl compound are
polymerized after preliminary polymerization in the presence of an
organolithium compound, a secondary amine compound, and isoprene.
[5] The method for producing a modified solution polymerized diene
rubber according to any one of the above mentioned [1] to [4],
wherein steam coagulation and drying in the step iv) is performed
in such a way that the content of two or more branched component
increases by 20 to 40% with respect to the state before the steam
coagulation and drying [6] The method for producing the modified
solution polymerization diene rubber according to any one of the
above mentioned [1], [3] and [5], wherein, after preliminarily
polymerizing isoprene of not more than 10% by weight of the total
monomers with an organolithium compound, another conjugated diene
compound and the aromatic vinyl compound are polymerized. [7] The
method for producing the modified solution polymerized diene rubber
according to any one of the above mentioned [1] to [6], wherein
after step iii) and before step iv), addition of the metal halide
compound of formula (3) in an amount satisfying the condition of
formula (4) is done, and then the steam coagulation and drying of
step iv) is performed. [Formula 3] (R.sup.4).sub.p-M-(X).sub.4-p
Formula (3) wherein, M is a tin atom or a silicon atom, R.sup.4 is
an alkyl group or aromatic group, wherein a carbon number of
R.sup.4 is 1 to 12, or an allyl group or a carboxy group, X is a
halogen compound of iodine, bromine or chlorine, p is an integer of
0 or 1. [Formula 4] L-(4-n)A.ltoreq.(4-p)B.ltoreq.2L Formula (4)
wherein, L is the amount of moles of the organolithium compound
added at the starting of the polymerization, A is the amount of
moles of the added tin compound of formula (1), B is the added
halogenated metal compound of formula (3), and n and p are integers
shown in formulae (1) and (3), respectively. [8] A rubber
composition comprising silica of at least 20-150 phr for 100 phr of
the total rubber component, wherein said 100 phr of the total
rubber component contains at least 20 phr of the modified solution
polymerized diene rubber according to any one of the above
mentioned [1] to [7]. [9] A rubber composition comprising silica of
at least 20-150 phr and carbon black of 5-30 phr for 100 phr of an
entire rubber component, wherein said 100 phr of the total rubber
component contains at least 20 phr of the modified solution
polymerized diene rubber according to any one of the above
mentioned [1] to [8].
That is, the first aspect of the present invention is, a method of
manufacturing modified solution polymerization diene rubber
comprising:
i) initiating polymerization of a conjugated diene compound and an
aromatic vinyl compound in a hydrocarbon, by an organic lithium
compound along or by coexisting organic lithium compound and
secondary amine compound;
ii) after completion of the polymerization, treating to make the
amount of the 3 or more branches of the components of the diene
rubber is 5 to 30% by adding a tin compound represented by the
formula (1); iii) then adding a silane compound represented by
formula (2), and treat to make the amount of 2 branch component of
the diene rubber is 30% or less; and iv) steam coagulating and
drying the resulting polymer composition, so that the content of 2
or more branch components is increased by 10-50% with respect to
the state before steam coagulation, whereas stabilized to the
extent that the Mooney viscosity (a) of the rubber after steam
coagulation and drying is different from the Mooney viscosity (b)
of the rubber after further treatment of 130.degree. C. roll mill
for 20 minutes heat, by only 10 or less. [Formula 1]
(R.sup.1).sub.n--Sn--(X).sub.4-n (1) wherein, R.sup.1 is an alkyl
group, an allyl group or an aromatic group, wherein a carbon number
of R.sup.1 is 1-12, X is a halogen compound of iodine, bromine or
chlorine, n is an integer of 0 or 1. [Formula 2]
(R.sup.2O).sub.m--Si--(R.sup.3).sub.4-m (2) wherein, R.sup.2 is an
alkyl group, an allyl group or an aromatic group, wherein a carbon
number of R.sup.2 is 1-12, or an alkyl group, an aromatic group or
an allyl group containing a nitrogen atom in these functional
groups, R.sup.3 is an alkyl group, an allyl group or an aromatic
group, wherein a carbon number of R.sup.3 is 1-12, or an alkyl
group, an aromatic group or an allyl group containing an oxygen
and/or nitrogen atom in these functional groups. m represents an
integer of 2-4
The second aspect of the present invention relates to more optimal
methods for manufacturing the modified solution polymerization
diene rubber.
After aforementioned step iii) and before the step iv), the
addition of the metal halide compound represented by the formula
(3) satisfying the condition of formula (4) is done, and then the
steam coagulation and drying of step iv) is done. [Formula 3]
(R.sup.4).sub.p-M-(X).sub.4-p (3) wherein, M is a tin atom or a
silicon atom, R.sup.4 is an alkyl group or an aromatic group,
wherein a carbon number of R.sup.4 is 1 to 12, or allyl group or a
carboxyl group, X is a halogen compound of iodine, bromine or
chlorine, p is an integer of 0 or 1. [Formula 4]
L-(4-n)A.ltoreq.(4-p)B.ltoreq.2L (4) wherein, L is the number of
moles of the organolithium compound added to the polymerization
initiation, A is the number of moles of added tin compound of the
formula (1), B is the number of moles of added metal halide
compound represented by the formula (3), n and p are integers
appear in respective formula (1) and (3).
The third aspect of the present invention relates to silica
containing rubber composition containing above explained modified
solution polymerization diene rubber 20 phr or more of the total
rubber component.
The Effect of the Present Invention
The present invention relates to a method for producing a modified
solution polymerized diene rubber for blending of silica having
excellent physical properties such as excellent strength and
resilience and a rubber composition thereof. Desolvation is good,
storage stability is excellent and workability is good.
BEST MODE FOR CARRYING OUT THE INVENTION
As the conjugated diene compound used in the present invention,
1,3-butadiene, isoprene, 1,3-pentadiene (piperylene),
2,3-dimethyl-1,3-butadiene, 1,3-hexadiene, etc. can be exemplified.
Among these, because of the availability and from the viewpoint of
the physical properties of the resulting modified solution
polymerization diene rubber, 1,3-butadiene and isoprene are
preferable. Especially 1,3-butadiene is preferable.
The used amount of the conjugated diene compound is generally 40 to
100 wt % of the total monomer, preferably 50 to 95 wt %. If less
than 40 wt %, hysteresis loss increases. A the aromatic vinyl
compound used in the present invention, styrene,
.alpha.-methylstyrene, vinyl toluene, vinyl naphthalene,
divinylbenzene, trivinylbenzene, and divinyl naphthalene can be
exemplified. Among them, because of the availability and from the
viewpoint of the physical properties of the resulting modified
solution polymerization diene rubber, styrene is preferred.
The amount of the aromatic vinyl compound is usually 60 wt % or
less in the total monomers, preferably 50 to 5 wt %.
As organolithium compounds used in the present invention is a
lithium compound having 2 to 20 carbon atoms. For example, ethyl
lithium, n-propyl lithium, iso-propyl lithium, n-butyl lithium,
sec-butyl lithium, tert-butyl lithium, tert-octyl lithium, n-decyl
lithium, phenyl lithium, 2-naphthyl lithium, 2-butyl-phenyl
lithium, 4-phenyl-butyl lithium, cyclohexyl folithium,
4-cyclopentyl lithium, 1,4-dilithio-a butene-2 and the like.
Preferable from industrial availability and stability, n-butyl
lithium, sec-butyl lithium, tert-butyl lithium are preferable, and
n-butyl lithium, sec-butyl lithium are more preferred.
The secondary amine compound used in the present invention is a
compound represented by the formula (5) or (6).
##STR00001## wherein, R.sup.5, R.sup.6 is an alkyl group having 1
to 20 carbons, a cycloalkyl group or an aralkyl group, R.sup.5 and
R.sup.6 may be the same or different, and R.sup.7 is divalent
alkylene having 3 to 12 methylene groups, bicycloalkane, oxy- or
amino-alkylene group.
As the R.sup.5, R.sup.6 of formula (5), for example, are methyl,
ethyl, butyl, hexyl, octyl, cyclohexyl, 3-phenyl-1-propyl, isobutyl
and the like. Specifically, methylethylamine, diethylamine,
dibutylamine, ethylbutylamine, dihexylamine, dioctylamine, butyl
octyl amine, octyl cyclohexylamine, diisobutylamine, butyl
(3-phenyl-1-propyl) amine and the like. From industrial
availability and solubility in a hydrocarbon solvent, dioctyl amine
and dihexyl amine are preferred.
The R.sup.7 groups of formula (6) comprises, for example,
trimethylene, tetramethylene, hexamethylene, oxydiethylene, N-alkyl
aza diethylene etc. Specific examples include pyrrolidine,
piperidine, hexamethyleneimine or heptamethyleneimine and the like.
Further, it may be 2 annular body such as decahydroisoquinoline or
perhydroindole. In particular, pyrrolidine, piperidine,
hexamethyleneimine or heptamethyleneimine are preferred.
As the monomers pre-polymerized in the existence of an organic
lithium compound and a secondary amine compound, those of faster
vulcanization rate than butadiene can be exemplified, specifically
those are isoprene, 1,3-pentadiene (piperylene), and 2,3
dimethyl-1,3-butadiene. Isoprene is more preferable from the
industrial availability and vulcanization rate.
As the tin compound represented by the formula (1), the following
compounds may be mentioned specifically. For example, tin
tetrachloride, ethyl tin trichloride, propyl tin trichloride, butyl
tin trichloride, octyl tin trichloride, cyclohexyl tin trichloride,
tin tetrabromide, ethyl tribromide tin, propyl tribromide tin,
butyl three tin bromide, octyl tribromide tin, cyclohexyl
tribromide, tin tetraiodide, tin, ethyl triiodide tin, propyl
triiodide tin, butyl triiodide tin, octyl triiodide tin, cyclohexyl
triiodide tin can be mentioned. Among them, preferred are tin
tetrachloride, octyl tin trichloride, a tin tetrabromide.
Particularly preferred is tin tetrachloride.
As the silane compound represented by the formula (2), the
following compounds may be mentioned specifically. For example
tetra-methoxysilane, tetra-ethoxysilane, tetrapropoxysilane,
tetrabutoxysilane, tetraphenoxysilane, tetratolylsilane,
methyltrimethoxysilane, methyltriethoxysilane,
methyltripropoxysilane, methyltributoxysilane,
methyltriphenoxysilane, ethyl trimethoxysilane, ethyl
triethoxysilane, ethyl tripropoxysilane, ethyl tributoxysilane
silane, ethyl triphenoxy silane, dimethyl dimethoxy silane,
dimethyl diethoxy silane, dimethyl dipropoxy silane, dimethyl
dibutoxy silane, dimethyl diphenoxy silane, diethyl
dimethoxysilane, diethyl diethoxysilane, diethyl di-propoxysilane,
diethyl dibutoxy silane, diethyl-diphenoxysilane,
vinyltrimethoxysilane, vinyltriethoxysilane, vinyl
tripropoxysilane, vinyl tributoxysilane silane, vinyl triphenoxy
silane, vinyl tri (2-methoxyethoxy) silane, vinyl tri (methyl ethyl
ketoxime) silane, methyl tri (methyl ethyl ketoxime) silane,
methyl tris (diethyl ketoxime) silane, ethyl tri (methyl ethyl
ketoxime) silane, ethyl tris(dimethyl ketoxime) silane, allyl
triphenoxy silane, octenyl trimethoxysilane, phenyl
trimethoxysilane, phenyl triethoxysilane, phenyl tripropoxy silane,
phenyl tributoxy silane, phenyl triphenoxy silane,
2-(3,4-epoxycyclohexyl) ethyltrimethoxysilane, vinyl tri
(methoxypropoxy) silane, methyl tris [2-(dimethylamino) ethoxy]
silane, methyl tris [2-(diethylamino) ethoxy] silane, methyl tris
[2-(dibutylamino) ethoxy] silane, ethyl tris [2-(dimethylamino)
ethoxy] silane, ethyl tris [2-(diethylamino) ethoxy] silane, ethyl
tris [2-(dibutylamino) ethoxy] silane, tetrakis [2-(dimethylamino)
ethoxy] silane, tetrakis [2-(diethylamino) ethoxy] silane, tetrakis
[2-(dibutylamino) ethoxy] silane and the like. Among these,
preferred are ketoxime silanes, and those hydrolysis thereof is
relatively easy: trimethoxy silanes, triethoxy silanes, tripropoxy
silane silanes, and amino ethoxy silanes which are estimated to
facilitate the reaction with the silica while increasing the
storage stability of the modified polymerization diene rubber.
Specific examples of amino alkoxy silane compound are shown below.
Dimethylamino methyltrimethoxysilane, 2-dimethylaminoethyl
trimethoxysilane, 3-dimethylaminopropyl trimethoxysilane,
4-dimethylamino butyl trimethoxysilane, dimethylaminomethyl
dimethoxy methyl silane, 2-dimethylaminoethyl dimethoxy methyl
silane, 3-dimethylaminopropyl dimethoxymethylsilane,
4-dimethylamino-butyl dimethoxy methyl silane, dimethylamino
methyltriethoxysilane, 2-dimethylaminoethyl triethoxysilane,
3-dimethylamino-propyltriethoxysilane, 3-diethylaminopropyl
trimethoxysilane, 4-dimethylamino-butyl triethoxysilane,
dimethylaminomethyldiethoxy methyl silane, 2-dimethylaminoethyl
diethoxy-methyl silane, 3-dimethylaminopropyl diethoxymethylsilane,
4-dimethylamino-butyl diethoxymethylsilane,
N-(3-triethoxysilylpropyl)-4,5-dihydroimidazole, N-allyl-aza-2,2
dimethoxy sila cyclopentane, and the like, and especially preferred
are 3-dimethylamino-propyltriethoxysilane, 3-diethylamino-propyl
triethoxysilane, 3-diethylamino-propyl trimethoxysilane.
As the alkoxysilane compound having a protecting group which
becomes a primary amino group after hydrolysis, for example N,N-bis
(trimethylsilyl)-3-aminopropyltrimethoxysilane, N, N-bis
(trimethylsilyl)-3-aminopropyltrimethoxysilane, N,
N-bis(trimethylsilyl)-3-aminopropyl tripropoxy silane, N, N-bis
(trimethylsilyl)-2-aminoethyl trimethoxy silane, N,
N-bis(trimethylsilyl)-2-aminoethyl methyldimethoxy silane and N,
N-bis (trimethylsilyl) aminoethyl methyl diethoxy silane,
1-trimethylsilyl-2,2-dimethoxy-1-aza-2-silacyclopentane, N,
N-diethyl-3-aminopropyl-trimethoxy silane, N,
N-diethyl-3-aminopropyltriethoxy silane, 2-(triethoxysilylethyl)
pyridine, .gamma.-isocyanate propyl triethoxysilane and the like
can be exemplified.
As the halogenated metal compound represented by the formula (3),
the following compounds may be mentioned specifically.
For example, as the tin compound represented by the formula (1),
tin tetrachloride, ethyl tin trichloride, propyl tin trichloride,
butyl tin trichloride, octyl tin trichloride, cyclohexyl tin
trichloride, tin tetrabromide, ethyl tin tribromide, propyl tin
tribromide, butyl tin tribromide, octyl tin tribromide, cyclohexyl
tin tribromide, tin tetraiodide, ethyl tin triiodide, propyl tin
triiodide, butyl tin triiodide, octyl tin triiodide, and cyclohexyl
tin triiodide can be exemplified. As the silicon compound, silicon
tetrachloride, methyl silicon trichloride, ethyl silicon
trichloride, propyl silicon trichloride, butyl silicon trichloride,
octyl silicon trichloride, cyclohexyl silicon trichloride, silicon
tetrabromide, methyl silicon tribromide, ethyl silicon tribromide,
propyl silicon tribromide, butyl silicon tribromide, octyl silicon
tribromide, cyclohexyl silicon tribromide, silicon tetraiodide,
ethyl silicon triiodide, propyl silicon triiodide, butyl silicon
triiodide, octyl silicon triiodide and cyclohexyl silicon triiodide
can be exemplified. Among these, preferred are silicon
tetrachloride, methyl silicon trichloride, ethyl silicon
trichloride, tin tetrachloride, octyl tin trichloride. Particularly
preferred are silicon tetrachloride, methyl silicon
trichloride.
Conditions of usage of the raw material, such as the amount and the
reaction temperature, reaction time for the production of the
solution polymerization diene rubber are as follows.
For the solution polymerization of the diene rubber, commonly
practiced method is used, that is: the conjugated diene compound or
the aromatic vinyl compound are polymerized in the condition of
temperature 10-120.degree. C. for several tens of minutes to
several hours, in the presence of an organic lithium compound and
polar compounds such as an ether compound or an amine compound.
The amount of the organic lithium compound to be used, is usually
better to be in the range of 0.1 to 10 millimoles per 100 g of
diene rubber. When less than 0.1 millimol, molecular weight becomes
too high, and MV viscosity and the solution viscosity become too
high, which cause problems in rubber production processes and tire
manufacturing processes. When it exceeds 10 millimol, the molecular
weight of the diene rubber becomes too low, and vulcanizate
properties is greatly reduced.
In the polymerization, as the ether compound for adjusting the
microstructure, the vinyl content in particular, of the diene
monomer portion of the diene rubber, such as diethyl ether,
di-n-butyl ether, ethylene glycol diethyl ether, ethylene glycol
dibutyl ether, diethylene glycol dimethyl ether, propylene glycol
dimethyl ether, propylene glycol diethyl ether, propylene glycol
dibutyl ether, tetrahydrofuran (THF), 2,2-di (2-tetrahydrofuryl)
propane (DTHFP), bis tetrahydrofurfuryl formal, tetrahydrofurfuryl
alcohol methyl ether, tetrahydrofurfuryl alcohol ethyl ether,
tetrahydrofurfuryl alcohol butyl ether, alpha-methoxy
tetrahydrofurane, dimethoxybenzene, and dimethoxyethane are
used.
As the amine compound, tertiary amines such as, triethylamine,
pyridine, N, N, N', N'-tetramethylethylenediamine,
dipiperidinoethane, N, N-diethylethanolamine methyl ether, N,
N-diethylethanolamine ethyl ether, N, N-diethylethanolamine butyl
ether are used.
As preferred compounds, considering the polymerization rate and the
modification efficiency, tetrahydrofuran (THF), 2,2-di
(2-tetrahydrofuryl) propane (DTHFP) and the like can be
exemplified. The amount of the addition of these compounds is
usually 0.01 to 10 mol, and preferably from 0.2 to 5 mol, per 1 mol
of the organic lithium compound which includes such as a plurality
of N atoms and O atoms. Compounds having one O atom in the
molecule, such as tetrahydrofuran for solvent, are preferably added
in an amount of 0.05 to 10%.
The polymerization reaction is carried out in a hydrocarbon
solvent. Suitable hydrocarbon solvents is selected from aliphatic
hydrocarbons, aromatic hydrocarbons, and alicyclic hydrocarbons, in
particular propane having 3 to 12 carbon, n-butane, iso-butane,
n-pentane, iso-pentane, n-hexane, cyclohexane, n-heptane, propene,
1-butene, iso-butene, trans-2-butene, cis-2-butene, 1-pentene.
2-pentene, 1-hexene, 2-hexene, benzene, toluene, xylene,
ethylbenzene. Preferably, n-pentane, iso-pentane, n-hexane,
cyclohexane, n-heptane. These solvents may be used by mixing two or
more.
In the present invention, mainly conjugated diene compounds, or a
conjugated diene compound and an aromatic vinyl compound are
polymerized by anionic polymerization, then the active diene rubber
is coupled with tin compounds, and then reacted by a silane
compound. These modification reaction is usually, 0-120.degree. C.,
preferably 50-100.degree. C., the reaction time is 1-30 minutes,
preferably 5-20 minutes.
As for the mode of the polymerization process used in the present
invention, both batch polymerization process and continuous
polymerization process are possible. The batch polymerization
method is suitable for modified solution polymerization diene
rubber having special features in resilience, and the continuous
polymerization process is suitable for those having special
features in wear resistance and workability.
In step ii), firstly, by adding a tin compound represented by the
formula (1) into the active diene rubber before modification, a
coupled diene rubber being tri- or more-functional with tin
compounds is prepared. The ratio of 3 or more branch components of
the diene rubber is preferably between 5-30%. When it is less than
5%, reactivity with carbon black, being usually used in combination
with silica, is reduced, and in steam desolvation process and in
drying step, crumbs (undried mass of the rubber having a few
millimeters to several centimeters) stick each other so drying is
difficult. When it exceeds 30%, the component that reacts with the
silica decreases, and rubber vulcanizate property of the silica
compounded is decreased. Thus, more preferred ratio of 3 branch
component of the diene rubber is 10-25%. The specific case of tin
tetrachloride is 0.0125-0.075 mole equivalents relative to the
active diene rubber. More preferably from 0.0125-0.05 mole eq. The
proportion of these branching structures can be measured by
GPC.
In step iii), by adding a silane compound represented by the
formula (2), two-branch structure of the diene rubber is made to be
30% or less. The amount of the silane compound used in said
addition is, an amount corresponding to 0.8-2 times, more
preferably 1.0-1.5 times, of the number of molecules per one
remaining active diene rubber molecule in step ii). If it is less
than 0.8, reactivity with the small number becomes silica
alkoxysilyl group introduced into the active diene rubber is
lowered. If it is more than twice, storage stability worsens.
However, the modified solution polymerization diene rubber, having
the structure of a diene rubber added with one molecule of silane
compound, causes a problem of being highly unstable, and rising of
Mooney viscosity during storage. Therefore, in order to convert the
structure to be being stable at the time of storage, and reactive
at the time of rubber and silica reaction, drying is done after
steam coagulation so as to increase the component of 2 or more
branches by 10-50%.
According to the present invention, branch structure after steam
coagulation and drying is estimated to be a two-branch structure
-A, and to be stable during rubber storage and has high reactivity
with silica when compounded. The 2 branch structure -A is estimated
to have been produced by condensation reaction of (Rubber) --Si--OH
which is made by hydrolyzing (Rubber) --Si--OR, and the (Rubber)
--Si--OR is made by modification with a silane compound of formula
(2). Reactivity with the conventional 2 branch structure --B and
silica is low. Therefore, it is preferable to increase the
proportion of 2 branch structure -A, this ratio is preferably 10 to
50%. When the ratio is less than 10%, Mooney viscosity stability
during storage is poor, and when it is more than 50%, production
condition is narrow and productivity is poor, therefore not
economical. More preferable ratio is from 20 to 40%. 2 branch
structure A (structure of the present invention):(Rubber)
--Si--O--Si-- (Rubber) 2 branch structure B (conventional
structure):(Rubber) --Si-- (Rubber) Ratio, etc.
The ratio of these branch structures are obtainable by GPC of the
manufacturing process.
For further improvement of the storage stability and the drying
step, in the present invention, firstly the coupling of the active
diene rubber by tin compound of formula (1) is done in step ii),
then after step ii) step iii) follows and therein a silane compound
represented by the formula (2) and the active diene rubber are
reacted under the condition that the component of the two branch
structures is as little as possible. Further, before the steam
coagulation and drying of step iv), a metal halide compound of the
formula (3) may be added. The metal halide compound is added under
the condition satisfying formula (4), for neutralizing what is
deactivated by impurities contained in the solvent or monomer, or
the lithium compound produced as a by-product in the reaction with
the active diene rubber and the silane compound
The amount of addition of the metal halide compound is L-(4-n)
A.ltoreq.(4-p) B.ltoreq.2 L is preferred. More preferably from
L-(4-n)A.ltoreq.(4-p)B1.5 L.
In case of L-(4-n)A>(4-p) B, neutralization is insufficient and
workability during steam coagulation of modifier solution
polymerization diene rubber, and storage stability are
deteriorated. In case of (4-p) B>2 L, acidity becomes too
strong, storage stability worsens, and causes such as metal
corrosion problems.
The weight average molecular weight of the modified solution
polymerized diene rubber obtained in the present invention is
100,000-1,000,000 as converted of polystyrene molecular weight,
preferably 150,000-700,000.
If the weight average molecular weight is less than 100,000, the
obtained rubber composition has insufficient strength, abrasion
resistance, impact resilience, etc. On the other hand, when it
exceeds 1,000,000, the processability is inferior and the
dispersibility of the filler during kneading deteriorates and
strength, abrasion resistance, impact resilience, etc.
deteriorate.
Mooney viscosity (Abbreviated as MV, may be referred to measurement
conditions are the ML 1+4/100.degree. C.) of the modified solution
polymerization diene rubber obtained in the present invention is
preferably in the range of 20 to 150, if it is less than 20,
abrasion resistance, rebound resilience is deteriorated, whereas,
the workability is reduced if it is more than 150.
Vinyl content of the diene portion of the diene-based modified
solution polymerization rubber of the present invention is
generally varied in the range of 20-80%. In view of the
vulcanization characteristics of the diene rubber, preferable range
is 30 to 70%. Vinyl content in the case of emphasizing wear
resistance is to be lower, the vinyl content is to be higher in the
case of emphasizing braking performance on wet road surface.
Extender oil can be added to a polymerization reaction solution
containing a modified solution polymerization diene rubber of the
present invention. The extender oils of those commonly used in the
rubber industry, such as paraffinic extender oil, aromatic extender
oil, and naphthenic extender oil can be used.
Pour point of the extender oil is preferably between minus 20 and
50.degree. C., more preferably minus 10 and 30.degree. C. In this
range, extended easily, the rubber composition having excellent
tensile properties and low heat buildup of the balance is obtained.
Suitable aromatic carbon content of extender oil (CA %, Kurtz
analysis) is preferably 20% or more, more preferably 25% or more,
and preferably paraffin carbon content of extender oil (CP %) is
55% or less, more preferably 45% or less. When CA % is too small,
or CP % is too large, the tensile properties is insufficient. The
content of polycyclic aromatic compounds in the extender oil is
preferably less than 3%. The content is determined by IP346 method
(testing method of The Institute Petroleum of UK.).
The content of the extender oil of the rubber composition is, for
100 parts by weight of the rubber composition, preferably 1 to 50
parts by weight, more preferably 5 to 30 parts by weight. When the
content of the extender oil is in this range, the viscosity of the
rubber composition containing silica becomes moderate, and tensile
properties and low heat build is excellently well-balanced.
When using the modified solution polymerization diene rubber of the
present invention as a rubber composition for a tire, it is
possible to use, as far as within the range that does not
essentially impair the effects of the present invention, natural
rubber, isoprene rubber, butadiene rubber, and emulsion-polymerized
styrene-butadiene rubber for blending, with a reinforcing agent,
and various additives such as silica and/or carbon black, and after
kneaded by a roll mill, a Banbury mixer, by adding a vulcanization
accelerator, sulfur, etc. and the rubber can become a rubber for a
tire such as a tread, a sidewall and a carcass. These compositions
can also be used for belt, vibration-proof rubber and other
industrial goods.
As a reinforcing material to be filled when the modified solution
polymerization diene rubber of the present invention is used in a
tire, especially in a tire tread, a filler having a hydroxyl group
on the surface, such as silica or the like, is optimal. It is also
possible to use a combination of carbon black. Filling amount of
the filler relative to the total rubber component of 100 phr, is
preferably 20-150 phr, more preferably 30-100 phr.
As silica, for example, dry silica, wet silica, colloidal silica,
precipitated silica and the like can be used. Among these, wet
silica composed mainly of hydrous silicic acid is particularly
preferred. These silica may be used alone or in combination of two
or more thereof. The particle size of the primary particles of the
silica is not particularly limited, but 1-200 nm, more preferably
3-100 nm, particularly preferably 5-60 nm. With the particle size
of the primary particles of silica is within this range, excellent
tensile properties and low heat build-balanced are achieved. The
particle size of the primary particles can be measured by an
electron microscope or a specific surface area and the like.
It is preferable to blend a silane coupling agent into the rubber
composition of the present invention in the rubber compounding, for
the purpose of further improvement of tensile properties and low
heat build-up. Examples of the silane coupling agents are:
.beta.-(3,4-epoxycyclohexyl) ethyltrimethoxysilane,
N-(.beta.-aminoethyl)-. .gamma.-aminopropyltrimethoxysilane,
tetrasulfide group such as bis (3-triethoxysilylpropyl)
tetrasulfide, bis (3-triethoxysilylpropyl-iso-propoxy)
tetrasulfide, bis (3-tributoxysilylpropyl) tetrasulfide,
.gamma.-trimethoxysilylpropyl dimethylthiocarbamoyl tetrasulfide,
.gamma.-trimethoxysilylpropyl benzothiazyl tetrasulfide, and bis
(3-triethoxysilylpropyl) disulfide, bis (3-tri-iso-propoxy silyl
propyl) disulfide, bis (3-tributoxysilyl propyl) disulfide,
.gamma.-trimethoxysilylpropyl dimethyl thiocarbamoyl disulfides,
.gamma.-trimethoxysilylpropyl benzothiazyl disulfide and the
like.
Because to avoid scorch during kneading, silane coupling agent is
preferably those sulfur contained in the molecule is 4 or less.
More preferably sulfur is 2 or less. These silane coupling agents
may be used alone or in combination of two or more.
The amount of the silane coupling agent with respect to 100 parts
by weight of silica is, preferably 0.1 to 30 parts by weight, more
preferably 1 to 20 parts by weight, particularly preferably 2 to 10
parts by weight.
As the carbon black, of the grade of N110, N220, N330, N440, N550,
and the like can be used. Carbon blacks may be used alone or in
combination of two or more thereof. The specific surface area of
carbon black is not particularly limited, but a nitrogen absorption
specific surface area (N 2 SA) is preferably 5-200 m.sup.2/g, more
preferably 50-150 m.sup.2/g, particularly preferably 80-130
m.sup.2. When the nitrogen adsorption specific surface area is
within this range, more excellent tensile properties can be
obtained. Further, DBP adsorption amount of carbon black is also
not particularly limited, but it is preferably 5-300 ml/100 g, more
preferably 50-200 ml/100 g, particularly preferably 80-160 ml/100
g. When DBP adsorption is within this range, a rubber composition
having more excellent tensile properties are obtained. Further, as
the carbon black, a high-structure carbon black, as disclosed in JP
A H05-230290, which has specific surface area by the adsorption of
cetyltrimethylammonium bromide is 110-170 m.sup.2/g, DBP (24M4DBP)
oil absorption under 4 times high pressure of 24,000 psi is 110-130
ml/100 g can be used and improves abrasion resistance of rubber
compound.
The amount of carbon black is, per 100 parts by weight of the
rubber component, 1-50 parts by weight, preferably 2 to 30 parts by
weight, particularly preferably 3 to 20 parts by weight.
Incidentally, the rubber composition of the present invention, can
use a vulcanizing agent, based on the total rubber components 100
phr, preferably in the range of 0.5-10 phr, more preferably 1-6
phr.
As the vulcanizing agent, typically sulfur, other sulfur-containing
compounds and such as peroxides can be exemplified.
Further, vulcanization accelerators such as sulfenamide, guanidine
and thiuram group may be used in conjunction with vulcanizing
agent, at an amount according to the necessity. Furthermore, zinc
white, vulcanization auxiliaries, antioxidants processing aids, and
so on, may be used at an amount according to the necessity.
Further, various additives to the rubber composition obtained by
using the modified solution polymerization diene rubber of the
present invention is not particularly limited, but as the purpose
of processability improver when kneading, or as further improving
the balance of wet skid characteristics, rebound resilience, wear
resistance, such as vulcanizing agent to be blended with other
extender oil and conventional rubber composition, vulcanization
accelerator, zinc white, antioxidant, scorch retarder, tackifier,
and compatibilizers including epoxy group-containing compounds,
carboxylic acid compounds, carboxylic acid ester compounds, ketone
compounds, ether compounds, aldehyde compounds, organic compounds
selected from hydroxyl group-containing compounds and amino group
containing compound or alkoxysilane compounds, silicone compounds
selected from siloxane compounds and aminosilane compound can also
be added at the time of kneading.
Next, the present invention is further explanation in detail using
embodiments, but the present invention is not limited by these
examples. The physical properties of the polymers were measured
according to the following methods.
Measurement of weight-average molecular weight (Mw) of the polymer
was carried out by gel permeation chromatography "GPC; Tosoh
HLC-8020, column: Tosoh GMHXL (2 in series)" using a differential
refractive index (RI), weight-average molecular weight (Mw) was
carried out in terms of polystyrene mono dispersed polystyrene as a
standard. Coupling efficiencies shown in Table 1 and Table 2 (Cp),
was calculated as follows. The "4 branch structure (Cp.sup.1) by Sn
compound" was determined using the tin tetrachloride, by the ratio
of the peak area of the GPC chart molecular weight of the uncoupled
diene rubber, and the peak area of corresponding coupled diene
rubbers having approximately four times the molecular weight. The
structure did not change substantially coupling efficiency even
when steam coagulation is carried out.
The sample for "2 branch structure by Si compound (Cp.sup.2)" is
taken out as polymerization solution immediately after the silane
compound-modification into a container sufficiently purged with
nitrogen, and analyzed after dilution. It was determined as a
percentage of the total peak area of the peak area of approximately
twice the molecular weight before coupling GPC chart. Peak area
corresponding to 3 branch structure by GPC chart after the silane
compound modified under the conditions of the present invention
were substantially negligible.
When "2 and more branch structure after steam coagulation
(Cp.sup.3)" is to be obtained, the increased 3 branch structure by
steam coagulation of diene rubber modified with a silane compound
overlaps with the coupling peak with tin compound. Therefore, we
calculated from the ratio of 2 times or more of the peak area of
the molecular weight prior to coupling. The "Increased coupling
efficiency increase after steam coagulation
(.DELTA.Cp=Cp.sup.3-Cp.sup.1-Cp.sup.2)" is the difference in
coupling efficiency before and after steam coagulation. Generally,
storage stability increases as this value is larger.
The "Steam coagulation test" shown in Table 1 and Table 2 were
carried out as follows, and determined by the following criteria:
Steam coagulation was carried out by putting normal dispersant into
a 50 L vessel equipped with a stirrer, and heated up to 90.degree.
C. with steam, and the polymerization solution 1 L is dropped from
the container with a hole of 35 diameter 3 mm for the duration of 5
minutes, and stirred for 60 minutes, while always maintaining the
90.degree. C. or higher. It was quantified according to the
produced crumb form or the like into 1 to 5. The larger the number,
the better.
5: Size of the crumb is homogeneous, crumbs do not adhere each
other even continued stirring. (no big problem in industrial
production is estimated)
3: Size of the crumb is slightly irregular, the adhesion amount of
crumb increases as the stirring is continued. (problem in
industrial production is likely, and some measures would be
necessary)
1: crumbs are irregular, adhesion of the crumbs occurs immediately
after the drop. (A big problem in industrial production will occur
and production is impossible. Some major technical aid is
indispensable.)
4,2: intermediate of the each.
Styrene unit content in the polymer was calculated from an integral
ratio of .sup.1H-NMR spectrum. The glass transition point of the
polymer (Tg) was measured using a Perkin Elmer differential
scanning calorimetry analyzer (DSC) 7 type apparatus, under the
conditions of the temperature, raised at 10.degree. C./min after
cooling to -100.degree. C.
Kneading properties, the physical properties of the vulcanized
rubber were measured by the following method and Mooney viscosity
of the rubber composition were measured in the following
manner.
Kneaded for preparing vulcanizate of the rubber
composition,--according to the JIS K6299: 2001 "rubber
manufacturing method of the test sample". Kneading of the rubber
composition containing no vulcanizing agent (A kneading) used
Laboplastomill of Toyoseiki Co., Ltd. As the conditions, filling
factor was about 65% (volume), rotor revolution was 50 rpm,
starting temperature was 90.degree. C. Kneading conditions (B
kneading) of blending a vulcanizing agent to the rubber composition
after A kneading was done by 8 inches roll of Daihan Co., Ltd.,
vulcanizer was blended at room temperature.
Temperature dispersion of viscoelasticity test was measured by a
"TA INSTRUMENTS Ltd. viscoelasticity measuring apparatus RSA3",
according to JIS K7244-7: 2007 "Plastics--Test method for dynamic
mechanical properties--Part 7:--Non-resonance method torsional
oscillation", the measurement frequency was 10 Hz, measuring
temperature was minus 50 to 80.degree. C., a dynamic strain of 0.1%
at a rising temperature rate of 4.degree. C./min, specimen size was
the "width 5 mm.times.length 40 mm.times.thickness of 1 mm". the
smaller tan .delta. (60.degree. C.) means low exothermic.
(2) Tensile properties, e.g. strength at break (T B), the modulus,
the elongation at break, the like was measured according to JIS
K6251: 2004.
Abrasion resistance was measured according to JIS K6264-2: 2005
"Rubber, vulcanized or thermoplastic--wear resistance of
Determination--Part 2: Test method" in Method B of Akron abrasion
test, the wear of the vulcanized rubber composition was measured.
The abrasion resistance was indicated by indices as abrasion
resistance index, and that of the control sample is set as 100. The
larger index the better.
Mooney viscosity was measured according to JIS K6300-2001. Mooney
viscosity [ML 1+4 at 100.degree. C.] was measured.
Mooney viscosity shown in Table 1 and Table 2 were calculated as
follows. "MV after steam coagulation and drying MV (a)" is measured
Mooney viscosity for a crumb obtained by steam coagulation at a
temperature 110.degree. C. of the roll, dried for 30 minutes. ".
After a 130.degree. C. roll mill MV (b)" is measured Mooney
viscosity for the rubber by additionally milled the rubber at
130.degree. C. for 20 minutes. After passing through 20 minutes
Mooney viscosity was measured. ".DELTA.MV" is the difference
between the MVs measured as above, which means an increase of MV
represented by (b-a), and smaller the value, the storage stability
is better.
EXAMPLE
[Example 1] and [Comparative Example 1]
The autoclave of 10 L internal volume was thoroughly purged with
dry nitrogen, cyclohexane 5500 g, were placed, 2,2-di
(2-tetrahydrofuryl) propane 556 mg (3.02 mmol) (DTHFP), 200 g (1.92
mol) styrene, 760 g (14.05 mol) of 1,3-butadiene were placed in the
autoclave. After adjusting the temperature in the autoclave to
25.degree. C., the reaction mixture of n-butyl lithium 322 mg (5.03
mmol), isoprene 10 g and piperidine 428 mg (5.03 mmol) in
cyclohexane was added to the autoclave, and the polymerization was
initiated. Polymerization temperature adiabatically raised, the
maximum temperature reached 88.degree. C. At this point,
1,3-butadiene 30 g was added, and further 5 minutes polymerization
carried out. Then added tin tetrachloride 52.4 mg (0.201 millimol),
were reacted for 5 minutes. Here, 20 mL of polymerization solution
was withdrawn from the autoclave into a vessel being sufficiently
substituted by nitrogen, for analysis, and later the 20 mL solution
was diluted and subjected to GPC analysis, and the rest was steam
coagulated. Then the methyl-tris [2-(dimethylamino) ethoxy] silane
1.29 g (4.20 mmol) was added to the autoclave, subsequently reacted
for 15 minutes. According to GPC analysis, the molar ratio of the
active diene rubber and the silane compound was 1.3. Further added
silicon tetrachloride 213 mg (1.26 mmol) and reacted for 5 minutes.
Finally, 2,6-di-tert-butyl-p-cresol was added to the polymerization
solution. The polymerization solution of 3000 g was dried by direct
desolvation method. This rubber was (Comparative Example 1). The
remaining solution was desolvated by steam coagulation method, and
dried at 110.degree. C. by the roll. This rubber was (Example 1).
The results of GPC analysis and the results of an analysis of the
styrene content of the diene rubber and vinyl content are
summarized in Table 1. Although the difference between Example 1
and Comparative Example 1 is drying method, direct desolvation
drying method of Comparative is Example 1 shows a major difference
in storage stability, and it is big problem for industrial
production.
Comparative Example 2
Except for adding 163 mg of tin tetrachloride, which is equivalent
to half an equivalent of n-butyl lithium used as the polymerization
initiator, the preparation of modified solution polymerization
diene rubber was carried out same as in Example 1. The analytical
results are summarized in Table 1. The 4 branch structure by Sn
compound has increased approximately 3-times as Example 1.
Example 2
Except that isoprene was ruled out from the preliminary
polymerization, the modified solution polymerization diene rubber
was prepared all the same as in Example 1. The analytical results
are summarized in Table 1. No particular big difference is seen
relating to production.
Comparative Example 3
Except that tin tetrachloride coupling was ruled out from Example
1, example 3 was prepared in the same manner as in the modified
solution polymerization diene rubber as in Example 1. The
analytical results are summarized in Table 1. Crumb adhesion of
each other in the steam coagulation tests are observed, is a big
problem for industrial production.
Example 3
Except that the isoprene was ruled out from the preliminary
polymerization and the addition of silicon tetrachloride was also
ruled out, sample was prepared in the same manner as in the
modified solution polymerization diene rubber as in Example 1. The
analytical results are summarized in Table 1. Although steam
coagulation test was slightly bad for the preparation, otherwise,
no significant difference was observed.
TABLE-US-00001 TABLE 1 Table 1 Polymerization recipe and analytical
results Comparative Comparative Comparative Dimension Example 1
Example 1 Example 2 Example 2 Example 2 Example 3 Styrene g 200 200
200 200 200 200 Butadiene-1 g 760 760 760 760 760 760 Butadiene-2 g
30 30 30 40 30 40 Isoprene g 10 10 10 0 10 0 Piperylene mg 428 428
428 428 428 428 n-ButylLithium mg 322 322 322 322 322 322 SnCl4 mg
52.4 52.4 163 52.4 0 52.4 Methyl-tris(2-dimethyl g 1.29 1.29 1.29
1.29 1.61 1.29 amino)ethoxy silane SiCl4 mg 213 213 213 213 213 0
Desolvation method Steam Direct Steam coagulation coagulation
desolvation Steam coagulation result 5 n.d. 5 5 2 4 Styrene content
% 20 20 20 20 20 20 Vinyl content % 61 61 59 62 59 60 Coupling
efficiency 4 Branched structure % 21 21 62 18 0 22 with tin
compound (Cp.sup.1) 2 and more branched structure % 22 22 5 25 25
28 with silicone compound(Cp.sup.2) 2 and more branched structure %
78 n.d. 75 76 68 71 after steam coagulation (Cp.sup.3) Increaded
coupling efficiency % 35 n.d. 8 33 43 21 after steam coagulation
.DELTA. Cp (Cp.sup.3 - Cp.sup.1 - Cp.sup.2) MV after steam
coagulation 83 38 71 79 72 77 and dried (a) MV after treated by
130.degree. C. 85 89 75 83 85 85 roll mill(b) .DELTA. MV; (b - a) 2
51 4 4 13 8
Example 4
Internal volume 10 L autoclave was sufficiently replaced with dry
nitrogen, and were added cyclohexane 5500 g, tetrahydrofuran 154 g
(THF), styrene 200 g (1.92 mol), 1,3-butadiene 760 g (14.05 mol).
After adjusting the temperature in the autoclave to 25.degree. C.,
piperidine 428 mg (5.03 millimol), and n-butyllithium 322 mg (5.03)
millimol) was added sequentially and directly into autoclave to
initiate polymerization. Polymerization adiabatically raised the
temperature and the maximum temperature reached 91.degree. C. At
this point, added the 1,3-butadiene 40 g, and the polymerization
was carried out for further 5 minutes. Then added tin tetrachloride
52.4 mg (0.201 millimol) and were reacted for 5 minutes. Here, 20
mL of polymerization solution was withdrawn from the autoclave into
a vessel sufficiently substituted by nitrogen for analysis, and
later diluted and GPC analysis was done, and the rest was steam
coagulated. Subsequently methyltriethoxysilane 0.861 g (4.83
millimol) has added in autoclave and reacted for 15 minutes.
According to GPC analysis, the molar ratio of the active diene
rubber and the silane compound was 1.5. Further, silicon
tetrachloride 213 mg (1.26 milllimol) was added and reacted for 5
minutes. Finally, 2,6-di-tert-butyl-p-cresol was added to the
polymerization solution. The solution was desolvated by steam
coagulation method and dried with the roll at 110.degree. C. This
rubber was Example 4. The results of the analysis are summarized in
Table 2.
Example 5
Except for increasing amounts of styrene into 250 g, decreasing
amount of the initial 1,3-butadiene into 710 g, without using
piperidine, modified solution polymerization diene rubber sample
was prepared all the same as in Example 4. The analysis results are
summarized in Table 2. No big difference is seen in relation to
production.
Example 6
Except for equimolar (N, N-dimethyl-3-aminopropyl) triethoxy silan
instead of methyl triethoxysilane, modified solution polymerization
diene rubber was prepared all the same as in Example 4. The
analysis results are summarized in Table 2. No big difference is
seen in relation to production.
Example 7
Except for the non-existence of the silicon tetrachloride addition
after the silane compound addition, a modified solution
polymerization diene rubber sample was prepared all the same as in
Example 6. The analysis results are summarized in Table 2. Steam
coagulation test has become a little worse, but the big difference
is not seen in relation to other aspects of production.
Comparative Example 4
Except for no use of tin tetrachloride after polymerization, no use
of piperidine as polymerization initiator component and no use of
silicon tetrachloride after the addition of the silane compound,
modified solution polymerization diene rubber sample was prepared
all the same as Example 6. The analysis results are summarized in
Table 2. Steam coagulation test becomes poor, and storage stability
was also greatly deteriorated.
TABLE-US-00002 TABLE 2 Table 2 Polymerization recipe and analytical
results Comparative Dimension Example 4 Example 5 Example 6 Example
7 Example 4 Styrene g 200 250 200 200 200 Butadiene-1 g 760 710 760
760 760 Butadiene-2 g 40 40 40 40 40 Isoprene g 0 0 0 0 0
Piperylene mg 428 0 428 428 0 n-ButylLithium mg 322 322 322 322 322
SnCl4 mg 52.4 52.4 52.4 52.4 0 Silane compound Methy triethoxy
silane (N,N-Dimethyl-3-amino propyle)triethoxy silane Amount of
silane compound g 0.861 0.749 1.05 1.05 1.05 SiCl4 mg 213 213 213 0
0 Desolvation method Steam coagulation Steam coagulation result 5 5
5 4 2 Styrene content % 20 25 20 20 21 Vinyl content % 61 59 62 60
59 Coupling efficiency 4 Branched structure % 21 25 22 23 0 with
tin compound (Cp.sup.1) 2 and more branched structure % 22 23 25 28
25 with silicone compound(Cp.sup.2) 2 and more branched structure %
80 77 70 71 61 after steam coagulation (Cp.sup.3) Increaded
coupling efficiency % 37 29 23 20 36 after steam coagulation
.DELTA. Cp (Cp.sup.3 - Cp.sup.1 - Cp.sup.2) MV after steam
coagulation and 85 78 76 72 56 dried (a) MV after treated by
130.degree. C. 86 82 78 79 78 roll mill(b) .DELTA. MV; (b - a) 1 4
2 7 22
Examples 8-14 and Comparative Examples 5-7
The modified solution polymerization diene rubber prototyped in
Comparative Examples 2 to 4 and Examples 1 to 7 were formulated
according to vulcanizate formulations of Table 3, and vulcanizate
properties were evaluated. Evaluation results are shown in Table 4.
Comparative Example 1 is very poor in storage stability, and
therefore omitted from property evaluation because there is a low
possibility of industrial use. In table 4, formation MV, Tensile
Strength, elongation at break, indicated modulus ratio M 300/M 100,
Akron abrasion resistance and the dynamic viscoelasticity test
results are shown. Physical properties are represented as index of
Comparative Example 5 as 100. For all items, larger index shows
better physical properties. Larger modulus ratio which is a measure
of the reinforcinforng properties, and lower compound MV are
better. While Comparative Example 5 has a low compound MV, modulus
ratio is small, and therefore considered as less reinforcing of
silica, and is not good in vulcanizate properties. Tensile strength
shows larger value as reinforcement with the silica is higher, and
a large Tensile strength value has a high correlation between Akron
abrasion resistance.
Tan .delta. index (0.degree. C.) is primarily governed by the
styrene content and the vinyl structure of diene rubber, and
significant differences was not found in any diene rubber
prototypes of the present invention. Tan .delta. index (60.degree.
C.) is influenced by dispersibility of silica and reinforcing by
silica. High reinforcing property and better dispersibility lead to
exhibit a larger value. From these physical property evaluation
results and the like, modified solution polymerization diene rubber
of the present invention is good in the productivity, has high
storage stability, yet has good vulcanizate properties.
TABLE-US-00003 TABLE 3 Table 3 Recipe of valcanized rubber compound
Recipe phr Rubber 100 Silica 70 Silane coupling agent Si69 6
Polyethylene glycol PEG4000 4 Carbon black N339 4 Aromatic oil 10
Zinc oxide 3 Stearic acid 2 Antioxidant 6C 1 Vulcanization
accelerator D 0.5 Vulcanization accelerator CZ 2.5 Sulfur 1.5 Total
204.5 Cf-1) phr; parts per hundred rubber. Cf-2) Si69;
bis(3-triethoxysilylpropyl) tetrasulfide Cf-3) PEG4000;
polyethylene glycol 4000 Cf-4) 6C;
N-phenyl-N'-(1,3-dimethylbutyl)-p-phenyldiamine Cf-5) D;
N,N'-diphenylguanidine Cf-6) CZ;
N-cyclohexyl-2-benzothiazolylsulfenamide
TABLE-US-00004 TABLE 4 Table 4 Vulcanized rubber property Example 8
Example 9 Example 10 Example 11 Example 12 Example 13 Modified
rubbe sample Example 1 Example 2 Example 3 Example 4 Example 5
Example 6 Compound MV (ML.sub.1+4/100.degree. C.) 75 77 74 71 68 70
Tencile strength at break (T.sub.B) MPa 24.6 22.6 21.5 22.1 24.9
23.1 Elongation at break (E.sub.B) % 430 410 420 390 380 415
Modulus ratio (M.sub.300/M.sub.100) 5.2 4.8 4.7 4.5 5 4.8 Acron
abrasion Index 165 152 148 150 159 156 Dynamic viscosity test tan
.delta. (0.degree. C.) Index 105 103 104 102 110 103 tan .delta.
(60.degree. C.) Index 163 150 147 145 141 149 Comparative
Comparative Comparative Example 14 Example 5 Example 6 Example 7
Modified rubbe sample Comparative Comparative Comparative Example 7
Example 2 Example 3 Example 4 Compound MV (ML.sub.1+4/100.degree.
C.) 69 61 80 84 Tencile strength at break (T.sub.B) MPa 21.9 15.3
19.2 18.8 Elongation at break (E.sub.B) % 420 520 480 455 Modulus
ratio (M.sub.300/M.sub.100) 4.6 2.5 4 3.8 Acron abrasion Index 145
100 140 135 Dynamic viscosity test tan .delta. (0.degree. C.) Index
105 100 101 102 tan .delta. (60.degree. C.) Index 138 100 131
125
* * * * *